In Mexico, a truck containing radioactive Cobalt-60 - a substance used in medical treatment - has been reported stolen, and there are new fears that the material could be used by terrorists to craft a "dirty bomb." CNN's Brian Todd reports.

Diners at Red Lobster and Olive Garden restaurants in Iowa and Nebraska caught an intestinal illness tied to a rare type of parasite after eating salad mix that came from Mexico, the U.S. Food and Drug Administration said Friday.

The federal agency said its investigators traced the outbreak to four "illness clusters" of restaurants, which spokeswoman Theresa Eisenman later identified to CNN as Red Lobster and Olive Garden locations. The probe didn't find indications that any bags of salad mix with the parasite - known as cyclospora - were sold at U.S. grocery stores.

Mexican President-elect Enrique Peña Nieto talks to Wolf Blitzer about the biggest problem in U.S.-Mexican relations. Peña Nieto, who will be inaugurated in four days, is meeting with President Obama today in Washington. The in-depth interview, which also includes discussion of Mexico's drug cartels, airs at 5pm ET on CNN.